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At command issuance (I/O registers setting contents)
1F7
(CM)
H
1F6
(DH)
H
1F5
(CH)
H
1F4
(CL)
H
1F3
(SN)
H
1F2
(SC)
H
1F1
(FR)
H
R = 0 or 1
At command completion (I/O registers contents to be read)
1F7
(ST)
H
1F6
(DH)
H
1F5
(CH)
H
1F4
(CL)
H
1F3
(SN)
H
1F2
(SC)
H
1F1
(ER)
H
*1 If the command is terminated due to an error, this register indicates 01.
(20)
READ BUFFER (X'E4')
The host system can read the current contents of the sector buffer of the device by issuing this
command. Upon receipt of this command, the device sets the BSY bit of Status register and
sets up the sector buffer for a read operation. Then the device sets the DRQ bit of Status
register, clears the BSY bit, and generates an interrupt. After that, the host system can read up
to 512 bytes of data from the buffer.
At command issuance (I/O registers setting contents)
1F7
(CM)
H
1F6
(DH)
H
1F5
(CH)
H
1F4
(CL)
H
1F3
(SN)
H
1F2
(SC)
H
1F1
(FR)
H
0
0
1
1
L
DV
Cylinder No. [MSB]
Cylinder No. [LSB] / LBA
Sector No.
Number of sectors to be transferred
xx
Status information
L
DV
Cylinder No. [MSB]
Cylinder No. [LSB] / LBA
Sector No.
00 (*1)
Error information
1
1
1
0
DV
xx
xx
xx
xx
xx
C141-E072-01EN
0
0
1
R
Head No. /LBA [MSB]
/ LBA
/ LBA [LSB]
Head No. /LBA [MSB]
/ LBA
/ LBA [LSB]
0
1
0
0
xx
5 - 41
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